Cold vs hot snare for large polyps: cold was safer, but doubled residual adenoma, most in high-grade dysplasia

Design

Individual patient data meta-analysis of four randomised trials

Population

1,423 patients with 1,509 non-pedunculated colorectal polyps ≥20 mm

Primary outcome

Major adverse events; residual or recurrent adenoma

Effect

Major AE 1.7% vs 5.9% (OR 0.26); residual adenoma 26.5% vs 12.8% (OR 2.61)

An individual patient data meta-analysis pooled four randomised trials of cold snare resection against hot snare endoscopic mucosal resection (EMR) for non-pedunculated colorectal polyps of 20 mm or more: 1,509 polyps (mean 31 mm) in 1,423 patients at 50 centres.

Major adverse events (deep mural injury, perforation or delayed bleeding) occurred in 1.7% after cold and 5.9% after hot resection (OR 0.26); cold snare was the only independent factor reducing them. Residual or recurrent adenoma was 26.5% against 12.8% (OR 2.61), and the difference grew with polyp size. The gap was smallest for sessile serrated lesions (15.0% against 8.1%) and largest in adenomas with high-grade dysplasia (40.8% against 18.0%).

This turns a 'which is better' debate into a selection decision. Cold resection makes sense for sessile serrated lesions and for patients at high bleeding or perforation risk, such as those on antithrombotics or with multimorbidity. For large adenomas, particularly with features suggesting high-grade dysplasia, hot EMR still gives more complete clearance.

• Assess lesion type and optical features before choosing the technique
• Favour cold snare for sessile serrated lesions of 2–4 cm
• Consider cold snare in patients on antithrombotics or with high procedural risk
• Favour hot EMR for large adenomas, especially with suspected high-grade dysplasia
• Whichever technique, arrange the 6-month scar check

Why it matters

The safer technique leaves twice as much adenoma behind, so the choice has to follow the lesion and the patient.

Don't overread it

Subgroup results come from a post hoc analysis, and the sessile serrated lesion difference did not reach significance (p = 0.053).

The statistics, in plain English

An odds ratio of 0.26 for major adverse events means about a quarter of the odds; in absolute terms about 4 fewer serious complications per 100 resections. The odds ratio of 2.61 for residual adenoma is about 14 more recurrences per 100. A significant interaction with size means the recurrence penalty of cold resection grows as polyps get larger.

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